Problem: Solve for $n$. $7n-4 = 31$ $n =$
Explanation: Let's add and then divide to get $n$ by itself. $\begin{aligned} 7n-4 &= 31 \\ \\ 7n-4 {+4}&= 31{+4}~~~~{\text{add }4} \text{ to each side}\\ \\ 7n-\cancel{ 4} {{+}\cancel{{4}}}&= 31{+4}\\ \\ 7n &=31{+4}\end{aligned}$ $\begin{aligned}7n &= 35 \\ \\ \dfrac{7n}{{7}} &= \dfrac{35}{{7}} ~~~~~~~\text{divide each side by } {7} \text{ to get } n \text{ by itself }\\ \\ \dfrac{\cancel{7}n}{\cancel{{7}}} &= \dfrac{35}{{7}} \\ \\ n &= \dfrac{35}{{7}} \end{aligned}$ The answer: $n={5}~~~~~~~~$ [Let's check our work!]